490 DISEASE IN WILD MAMMALS AND BIRDS 
twelve orders numbering 1,860 animals, whereas the latter 
represent the cases in fourteen of twenty orders num- 
bering 3,505 birds. The percentages are considerably 
increased by high figures for a few orders. Primates, 
Lemures, Columbae for examples. There are missing 
from the list very few orders of which we have any 
notable number of autopsies, Marsupialia and Herodiones 
being the only important ones ; it would seem that these 
orders have a high resistance to the disease. 
Investigation into the origin of the disease in mam- 
mals and birds shows with definiteness the preponderance 
of the alimentary route influence in the latter, but for the 
former the figures cannot be said to be conclusive. The 
bird excretes large numbers of bacilli with the feces 
thereby soiling the feed and the ground. This is due to 
the frequency of intestinal open lesions and to the really 
enormous numbers of bacilli which are in the morbid tis- 
sue. I think it can be said with safety that, other things 
being equal, the bird excretes bacilli constantly and in 
greater numbers than does the mammal, and that 
in physically comparable lesions there are more bacilli in 
the avian than in the mammalian. 
The inconclusive figures for the origin of the disease 
in the mammal can be clarified very little by the subtrac- 
tion from the tables of the figures for the very susceptible 
Primates. By doing this it would seem that the respira- 
tory route dominates as 43 to 29, whereas if the reasonably 
susceptible Lemures be also deducted the ratio becomes 
as 38 to 15. It would seem that the evidence favors the 
aerogenic route in the mammal. 
Pathological. Types. 
An inquiry into the gross pathological types reveals 
at once the frequency with which the nodular and massive 
caseous forms appear. If the number of cases be reduced 
to percentage it will be found that 59 per cent, of all 
specimens presented the nodular variety and 26.6 per 
